“…The second approach investigated the pattern of risk after first tumours: asynchronous constant or decreasing relative risks may favour shared risk factors, whereas increasing risks with increasing lead time should point to treatment effects (Heard et al, 2005). There is an excellent literature on the development of bladder tumours after specific types of cancer, for example after prostate, oesophageal, testicular, cervical and lung tumours, and after lymphomas (Kaldor et al, 1987;Pettersson et al, 1990;Pathak Bjorge et al, 1995;Bokemeyer and Schmoll, 1995;Travis et al, 1995Travis et al, , 1997Levi et al, 1996Levi et al, , 1999Fisher et al, 1997;Teppo et al, 2001;Dores et al, 2002;Brennan et al, 2005;Heard et al, 2005;Liauw et al, 2006;Bostrom and Soloway, 2007;Chaturvedi et al, 2007;Kellen et al, 2007;Landgren et al, 2007;Muller et al, 2007;Chuang et al, 2008;Singh et al, 2008). The main advantage of this study was the simultaneous investigation of the most common types of cancer before bladder tumours using a uniform reference population.…”